I have just found that the Zdenek Houska's TV & video broadcast gear collector's youtube channel disappeared.
Although the channel was in Czech language only, there were many great interesting videos from old tube cameras, up to quite modern (yet still vintage) video processing equipment. Many teardowns of old tech, servicing of the extremely complex equipment (including video head refurbishing), etc.
I was just curious why there was no update of the Ampex repair series for a long time. Found the channel not existing. No clue what happened there, so RIP Zdenek's channel.